Ethernet differentiated services architecture

ABSTRACT

A network includes an edge node configured to define per hop behaviors using a set of bits in an Ethernet header of a frame and a core node configured to receive the frame and to forward the frame according to the per-hop-behaviors. The network can also include a defined set of differentiated service classes, each differentiated service class associated with the set of per hop behaviors, indicated in the set of priority bits. The network classifies the Ethernet frame based on at least one of a set of priority bits or information in at least one protocol layer in the frame header of the Ethernet frame and determines a per hop behavior based on the classification.

PRIOR APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication entitled “ETHERNET DIFFERENTIATED SERVICES” Ser. No.60/537,487 filed on Jan. 20, 2004

BACKGROUND

This invention relates to quality of service support in Ethernetnetworks.

Ethernet is a widely installed local area network (LAN) technology.Ethernet technology can be cost effective, easy to configure, and iswidely understood by network managers. Ethernet technology isincreasingly being deployed in service provider metro and wide-areanetworks. Success of Ethernet in provider networks depends on theability to provide service level agreements (SLAs) that can guaranteebandwidth, delay, loss, and jitter requirements to end-users. Serviceproviders can offer multiple services with different quality-of-service(QoS) characteristics and performance guarantees.

The base Ethernet technology is specified in the IEEE 802.3 standard.Traditionally, Ethernet did not include QoS capabilities. More recently,the IEEE has introduced the user priority capability that enables thedefinition of up to eight classes of service (CoS). The user prioritycapability is often referred to as “the p-bits.” The p-bits are carriedin the 802.1Q tag and are intended for use to identify different serviceclasses.

An Ethernet network may include multiple customer edge (CE) devices,switches, and routers. These devices may communicate using the Ethernetprotocols and/or other networking technologies and protocols.

SUMMARY

In one aspect, a system includes an Ethernet network. The Ethernetnetwork includes a set of edge nodes configured to define per hopbehaviors using a set of p-bits in the Ethernet header and a set of corenodes configured to forward the frame according to the per-hop-behaviorsas indicated in the p-bits.

In another aspect, a network includes a first Ethernet network and asecond Ethernet network. The first Ethernet network includes an edgenode configured to define per hop behaviors using a set of bits in anEthernet header of a frame and a core node configured to receive theframe and to forward the frame according to the per-hop-behaviors asindicated in the set of bits. The second network includes a second edgedevice in the second network configured to determine the Ethernetper-hop behavior for the frame.

Embodiments may include one or more of the following. The set of edgenodes can provide conditioning of the frames. The set of core nodes canforward the frame according to the per hop behaviors indicated in thep-bits. The set of edge nodes can include an ingress device and anegress device.

The edge node can include a classifier device, a marker deviceconfigured to mark the frame with a particular per-hop-behaviorindicated in the p-bits, and a shaper. Alternately, the edge node caninclude a classifier device, a marker device configured to mark theframe with a particular per-hop-behavior indicated in the p-bits, and adropper. The edge node can also include a meter device.

The set of core nodes can forward the frame according to a subset of allper-hop-behaviors. The set of edge nodes can add a tunnel header to theframe. The tunnel header can include a set of bits that indicate a perhop behavior. The tunnel header can use a Q-in-Q or MAC-in-MAC EthernetEncapsulation method. The system can preserve the information in theoriginal frame.

The system can also include boundary nodes between the multiple Ethernetdomains. The boundary nodes can map a per hop behavior of the framebetween the multiple networks. The boundary nodes can provide trafficconditioning for the frame. The system can also include customer edgedevice that sets the p-bits for the frame.

In another aspect, a system includes an Ethernet network. The Ethernetnetwork includes a set of edge nodes configured to define Ethernet perhop behaviors using a set of bits in a frame and a set of core nodesconfigured to forward the frame according to the Ethernetper-hop-behaviors, the core nodes using a different network technologythan the edge nodes.

Embodiments can include one or more of the following. The differentnetwork technology can be an asynchronous transfer mode technology, amulti-protocol label switching technology, a frame relay technology, oran Internet protocol technology. The set of edge nodes can map theEthernet per hop behaviors to a set of bits in a frame according to thedifferent network technology. The set of edge nodes can map the Ethernetper hop behaviors to a set of connections in the different networktechnology. The system can preserve a set of information in the frame.The set of edge nodes can encapsulate the frame and tunnel the frame fordelivery on the core nodes.

In another aspect, a networking device includes a behavior aggregateclassifier device configured to receive an Ethernet frame and classifythe frame based on the priority bits in the Ethernet header.

Embodiments can include one or more of the following. The device candetermine a bandwidth profile based on the classification. A meterdevice can meter the frames based on the bandwidth profile. A markerdevice can mark the frame header with a particular per-hop-behaviorindication. A shaper device can receive a frame from the marker anddetermine a behavior based on the per hop behavior. The marker can setthe priority bits in the frame to a particular combination.

The system can also include a frame meter device. The frame meter devicecan determine temporal properties of a set of frames. The shaper devicecan be a dropper and the dropper can drop the frame based on the per hopbehavior.

The networking device can include core switch configured to receive aframe from an ingress switch or another core switch. The core switch canapply a particular forwarding behavior to the frame based on the per hopbehavior as indicated in the priority bits. The networking device caninclude an egress switch configured to receive a frame from the ingressor the core switch. The ingress switch can include an encapsulationdevice and the core switch is one of an asynchronous transfer modeswitch, a multi-protocol label switching switch, a frame relay switch,or an Internet protocol router.

The above aspects or other aspects of the invention may provide one ormore of the following advantages.

Aspects may provide a scalable Ethernet differentiated servicesarchitecture that is capable of supporting different services andperformance characteristics. The architecture can accommodate a widevariety of services and provisioning policies. The Ethernetdifferentiated services architecture can allow for incrementaldeployment, and permitting interoperability with non-Ethernetdifferentiated services compliant network nodes.

A variation of the architecture where Ethernet is used at the access anda different technology at the network core provides an advantage ofallowing differentiated services across heterogeneous networks.

Ethernet differentiated services domains are multiple enterprise and/orprovider networks/segments that employ different Ethernet differentiatedservices methods and policies within each domain, such as differentp-bits interpretations, number/type of PHBs, etc. Mapping or trafficconditioning can be used at the boundary nodes between differentdomains.

Ethernet class of service (CoS) bits identifies nodal behavior (e.g.,how an incoming frame should be handled at queuing and scheduling levelsbased on p-bits encoding) and allows frames to be forwarded according tothe specified nodal behaviors. Ethernet per-hop-behaviors are determinedor encoded by a specific assignment of the p-bits. The p-bits can alsoinclude congestion information to indicate network congestion.

The particular use of the 802.1Q VLAN Tag Control Information (e.g.,p-bits) enables the introduction of the differentiated services toEthernet technologies. The use of the p-bits allows the definition of anumber of defined per hop behaviors (PHBs) that determine the forwardingtreatment of the Ethernet frames throughout the network.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of a tagged Ethernet frame.

FIG. 2 is a block diagram of an Ethernet differentiated servicesarchitecture.

FIG. 3 is a block diagram of a set of components included in a device atan edge node of a network.

FIG. 4 is a block diagram of an Ethernet differentiated servicesarchitecture.

FIG. 5 is a block diagram of Ethernet differentiated services per hopbehaviors.

FIG. 6 is block diagram of a class-based scheduler using multiplequeues.

FIG. 7 is table of priority bit assignments.

FIG. 8 is a block diagram of a differentiated services network havingmultiple domains.

FIG. 9 is an architecture for end-to-end service across multipleprovider networks.

DETAILED DESCRIPTION

Referring to FIG. 1, an example of an Ethernet frame 10 is shown. Theframe includes a header portion 12 and a data portion 14. The header 12includes a destination address 16, a source address 18, an 802.1Q tag20, and a protocol type 22. The Institute for Electrical Engineers(IEEE) standard 802.1Q describes the 802.1Q tag 20. The 802.1Q tag in anEthernet frame that defines a virtual-LAN (VLAN) membership. Three bitsof this tag, referred to as the priority bits 24, identify userpriority. The three priority bits 50 provide eight combinations anddescribe up to eight levels of service. The three priority bits can beused to describe the per-hop-behavior of a frame. Per-hop-behaviorsinclude for example, externally observable forwarding behavior appliedto a frame by a frame forwarding device 20 in an Ethernet differentiatedservices architecture 30.

Referring to FIG. 2, the Ethernet differentiated services architecture30 is shown. This architecture 30 forwards frames based on theper-hop-behaviors defined by the p-bits 24 for the frames. Oneembodiment of the architecture 30 includes a frame forwarding device 20that includes an ingress switch 34, a core switch 38, and egress switch46. The ingress switch 34 performs traffic conditioning functions andclass-based forwarding functions. The core switch 38 includes a behavioraggregate (BA) classifier 40 and a class-based egress scheduler thatuses multiple queues 44. The egress switch 46 may perform similarfunctions to either the ingress switch 34 or core switch 38 (or a subsetof those functions), depending on network configurations and policies.For example, if the egress switch 46 is connected to a customer edgenode, the egress switch 46 can perform core node-like forwardingfunctions. Alternately, if the egress switch 46 is connected to anotherprovider network using an network-network interface (NNI), the egressswitch 46 performs traffic conditioning functions according to theservice contract between the two providers. The architecture 30 includesEthernet differentiated services functions implemented at both the edgeand the network core 36, although other arrangements may be possible.

Unlike the IP DiffServ (“Differentiated services”) Architecture,described in RFC 2475, the architecture 30 shown in FIG. 2 does not usethe IP DSCP for indicating frame per-hop behaviors. Instead, thearchitecture 30 uses the Ethernet p-bits 24. Architecture 30 assumesthat edge and core nodes are p-bit aware nodes, meaning that e.g., thatthe nodes can set, clear and/or process frames based on the states ofthe p-bits. For example, all edge and core nodes are VLAN-aware Ethernetnodes that can set and/or interpret the p-bits. The network core 36 maybe an Ethernet network such as is common in enterprise networks or aprovider metro Ethernet network, and may use some Ethernettunneling/aggregation techniques such as stacked virtual large areanetworks (VLAN) support such as Q-in-Q (referring to the 802.1Q tag),Media access control in media access control (MAC-in-MAC, or anequivalent scheme.

The architecture 30 separates edge and network core node functions. Thatis, the edge includes traffic conditioning that may include multi-fieldclassification, metering, and marking of the Per-Hop Behavior (PHB) inthe p-bits 24, together with class-based forwarding. On the other handthe edge functions may occur at the user-network interface (UNI) forexample, between the customer edge (CE) node and service provider, or atthe network-network interface (NNI) between networks/domains. The corenode 36 is scalable and performs simple behavior and aggregateclassification based on the frame per-hop-behavior (PHB) (indicated inthe p-bits 24), and class-based forwarding based on the PHB value.

Referring to FIG. 3, components 50 included in a device at the networkedge nodes are shown. For example, the set of components 50 are includedin an ingress switch such as switch 34 (FIG. 2). The set of components50 includes a classifier 52, meter 54, marker 56, and shaper/dropper 58.These components 50 perform Ethernet traffic conditioning functions atthe network edge nodes to classify incoming traffic based onpredetermined criteria.

The classification identifies flows and correlates the flows tocorresponding bandwidth profiles for the flows and correspondingforwarding treatments defined or provided for the flows. The classifier52 selects frames in a traffic stream based on content of some portionof the frame header (e.g., based on the p-bits). Two types ofclassifiers include behavior aggregate (BA) classifiers and multi-field(MF) classifiers. A BA classifier classifies frames based on the p-bitsonly. The MF classifier on the other hand selects frames based on thevalue of a combination of one or more header fields, such as source anddestination address, p-bits, protocol ID, source and destination portnumbers, and other information such as incoming interface/connection. Ingeneral, classifier 52 (e.g., a behavior aggregate (BA) classifier ormulti-field (MF) classifier) is used to “steer” frames matching a ruleto a different element of the traffic conditioner for furtherprocessing.

Frames enter classifier 52 (indicated by arrow 51) and may or may not bemetered based on the service level agreement. Metered frames are passedto meter 54. Meter 54 measures the temporal properties of the stream offrames selected by a classifier and compares the properties to a trafficprofile. A meter 54 passes state information to other components totrigger a particular action for each frame that is either in- orout-of-profile. Non-metered frames are passed from classifier 52 tomarker 56.

Flows are marked (or remarked) by marker 56 to identify the Ethernet PHBapplied to the incoming frame. For instance, frame marker 56 sets aparticular field of a frame to a particular p-bit combination, addingthe marked frame to a particular behavior aggregate. The marker 56 canbe configured to mark all received frames to a single p-bit combination,or can be configured to mark a frame to one of a set of p-bitcombinations used to select a particular PHB from a PHB group accordingto the state of the meter 54.

A PHB group is a set of one or more PHBs that can be specified andimplemented simultaneously, due to a common constraint applying to allPHBs in the set such as a queue servicing or queue management policy. APHB group allows a set of related forwarding behaviors to be specifiedtogether (e.g., four dropping priorities). A single PHB is a specialcase of a PHB group. When the marker 54 changes the p-bit combination ina frame it is referred to as having “re-marked” the frame.

Remarking may also occur across Ethernet-differentiated services domainboundaries, such as a user to network interface (UNI) or network tonetwork interface (NNI) interface. Remarking could be used for suchpurposes as performing PHBs mapping or compression, or to effect p-bitstranslation.

If tunneling is used, the outer tunnel p-bits are usually also set tothe desired PHB indication for forwarding through the aggregated core.The p-bits in the original Ethernet frame may be preserved through thenetwork, or changed by the edge nodes.

Frames that exceed their assigned rates may be dropped, shaped, orremarked with a drop precedence indication. The shaper/dropper 58 shapesthe traffic before sending the frames to the network as indicated byarrow 60. Shaper/dropper 58 discards some or all of the frames in atraffic stream in order to bring the stream into compliance with atraffic profile. This discarding is sometimes referred to as “policing”the stream. A dropper can be implemented as a special case of a shaperby setting the shaper buffer size to zero (or a few) frames.

In general, multi-field traffic classification is based on any of theL1-L7 protocol layer fields, either individually or in combination.Common L2 Ethernet fields used are the incoming Ethernet Interface(port), the Destination/Source MAC addresses, the virtual local areanetwork identification (VLAN ID or VID), and the User Priority (p-bits).Based on the Destination/Source media access control (MAC) addresses allof the frames originating at a certain source and/or destined to acertain destination are assigned to the same flow. Thus, based on theVLAN ID all frames of a certain VLAN belong to the same flow.

Alternatively a Group of VLANs may be combined together for the purposeof class of service (CoS) functions. The user priority bits (p-bits 24)provide a finer granularity for flow identification.

The L2 Ethernet fields can be combined for traffic classification.Common combinations include: “port+p-bits”, “VID(s)+p-bits.” Commonupper layer fields include IP differentiated services, IP source, IPDestination, IP Protocol Type, TCP port number, UDP port number.

Frame classification determines the forwarding treatment and metering offrames. Determining the forwarding treatment (e.g., congestion control,queuing and scheduling) by the edge nodes includes assigning PHBs to thegroup of frames that require the same treatment (e.g. Voice is assignedE-EF PHB, and Data is assigned E-AFX PHB). Metering can be used fordetermining and enforcing the bandwidth profile/traffic contract, andverifying the Service Level Agreements (SLAs), and allocating nodalresource to the flow.

The classification function may be different for the purpose offorwarding and metering. For example, voice and data typically receivedifferent forwarding treatment, but their traffic bandwidth profilecould be combined into a single traffic contract to resemble a leasedline service.

Referring to FIG. 4, another example of an Ethernet differentiatedservices architecture 70 is shown. The architecture 70 includes aningress switch 84 at an interface between an Ethernet network 82 and anon-Ethernet network core 86. The architecture 70 also includes anegress switch 88. In this example, different technologies are used forforwarding the Ethernet frames through the non-Ethernet network core 86.For example, the non-Ethernet network core 86 could use asynchronoustransfer mode (ATM), multi-protocol label switching (MPLS), frame relay(FR), Internet protocol (IP), or other network protocols.

The ingress switch 84 includes a classifier 72, traffic meter 74, marker76, shaper/dropper 78, and a mapping unit 80. The classifier 72, trafficmeter 74, marker 76, and shaper/dropper 78 function in a similar mannerto those described above in FIG. 3. The mapping unit 80 maps andencapsulates the Ethernet frames for forwarding on the core network 86.

The architecture 70 shown in FIG. 4 is similar to architecture 30 shownin FIG. 2, however, architecture 70 uses Ethernet at the access, and adifferent networking technology in the core 86. The edge conditioningfunctions are similar to the edge conditioning functions in architecture30. The Edge node performs the class of service (CoS) mapping from theEthernet PHB into the core network 86. Many mapping methods are possiblesuch as mapping the PHB to an ATM virtual channel connection (VCC)(e.g., E-EF to constant bit rate (CBR) VCC), a link-state packet (LSP),an IP Differentiated services Core, etc. In all cases, the originalinformation in the Ethernet frame is maintained through transportthrough the core using tunneling and/or encapsulation techniques.

In the above example, frames are placed into class queues based on thePHB. Alternately, frames could be placed on different logical orphysical ports or connections with different levels of service based onthe PHB.

In both architecture 30 (FIG. 2) and architecture 70 (FIG. 4) edge CoSfunctions define per-hop behaviors for a frame. However, in architecture30, a frame is forwarded based on per-hop-behaviors indicated in thep-bits 24, whereas in architecture 70, a frame is forwarded based on thecore network technology CoS transport mechanism.

Referring to FIG: 5, a grouping 90 of the nodal behaviors into, e.g.,four categories is shown. The grouping 90 includes an Ethernet expeditedforwarding category 92 (E-EF), Ethernet assured forwarding 94 (E-AF),Ethernet class selector 96 (E-CS), and Ethernet default-forwardingcategory 98 (E-DF). Other groupings of behaviors are possible.

The first category, referred to as an Ethernet expedited forwardingcategory 92 (E-EF) is primarily for traffic sensitive to delay and loss.This category is suitable for implementing services that requiredelivery of frames within tight delay and loss bounds and ischaracterized by a time constraint. A frame arriving to a network nodeand labeled as an Ethernet EF frame departs the node according to a timeconstraint (e.g., d_(k)-a_(k) is less than or equal to t_(max) wherea_(k) and d_(k) are the arrival and the departure times of the k_(th)frame to the node and t_(max) is the time constraint). E-EF allows forframe loss when buffer capacity is exceeded, however, the probability offrame loss in this service is typically low (e.g., 10⁻⁵-10⁻⁷). E-EFidentifies a single drop precedence and frames that exceed a specifiedrate are dropped. For E-EF frames, no remarking (e.g., re-assigning thedrop precedence of frame to a different value) is allowed. The Ethernetexpedited forwarding category 92 does not allow re-ordering of frames.

A complete end-to-end user service can include edge rules orconditioning in addition to forwarding treatment according to theassigned PHB. For example, a “premium” service level (also be referredto as virtual leased line), uses E-EF PHB defined by a peak rate only.This “premium” service has low delay and small loss performance. A framein the E-EF category can have forwarding treatment where the departurerate of the aggregate frames from a diff-serv node is set to equal orexceed a configurable rate. This rate is available independent of othertraffic sharing the link. In addition, edge rules describe metering andpeak rate shaping. For example, the metering/policing can enforce a peakrate and discard frames in excess of the peak rate. Themetering/policing may not allow demotion or promotion. Peak rate shapingcan smooth traffic to the network and convert traffic to constant ratearrival pattern. A combination of the forwarding behaviors and edgerules offer a “premium” service level. A premium service queue typicallyholds one frame or a few frames. An absolute priority schedulerincreases the level of delay performance and could be offered initiallyon over-provisioning basis.

A second, more complex category, referred to as Ethernet assuredforwarding (E-AF) 94 divides traffic into classes of service, and whenthe network is congested, frames can be discarded based on a dropprecedence. More specifically, E-AF defines m (m>=1) classes with eachclass having n (n>1) drop precedence levels. Frames marked with highdrop precedence indication are discarded before frames with a low dropprecedence on nodal congestion. At the Ethernet traffic meter, E-AFframes that exceed their assigned rate may be marked with high dropprecedence indication (instead of dropping). The network typically doesnot extend any performance assurances to E-AF frames that are markedwith high drop precedence indication. The nodal discard algorithm treatsall frames within the same class and with the same drop precedence levelequally. E-AF per-hop-behavior does not allow re-ordering of frames thatbelong to the same flow and to the same E-AF class.

A third category, referred to as an Ethernet Class Selector (E-CS) 96provides compatibility with legacy switches. Ethernet Class Selectorincludes up to eight p-bit combinations. For example, E-CS7 to E-CSOwith E-CS7 assigned the highest priority and E-CSO assigned the lowestpriority. E-CS frames can be metered at the network edge. E-CS does notallow significant re-ordering of frames that belong to the same CSclass. For example, the node will attempt to deliver CS class frames inorder, but does not guarantee that re-ordering will not occur,particularly under transient and fault conditions. All E-CS framesbelonging to the same class are carried at the same drop precedencelevel.

The fourth category, a default-forwarding category 98 (E-DF), issuitable for implementing services with no performance guarantees. Forexample, this class can offer a “best-effort” type of service. E-DFframes can be metered at the network edge. This class of service shouldnot allow (significant) re-ordering of E-DF frames that belong to thesame flow and all E-DF frames are carried at the same drop precedencelevel.

Frame treatment can provide “differentiated services”, for example,policing, marking, or re-coloring of p-bits, queuing, congestioncontrol, scheduling, and shaping. While, the proposed Ethernet per hopbehaviors (PHB) include expedited forwarding (E-EF), assured forwarding(E-AF), default forwarding (E-DE), and class selector (E-CS), additionalcustom per hop behaviors PHBs can be defined for a network. The threep-bits allow up to eight PHBs). If more PHBs are desired, multipleEthernet connections (e.g. Ethernet interfaces or VLANs) can be used,each with up to eight additional PHBs. The mapping of the p-bits to PHBsmay be signaled or configured for each interface/connection.Alternatively, in the network core, tunnels may be used for supporting alarger number of PHBs.

Referring to FIG. 6, an arrangement 100 for placing an incoming frame101 in an appropriate class queue based on its p-bits 24 is shown. Thearrangement 100 includes four queues 102, 104, 106, and 108. The queues102, 104, 106, and 108 are assigned different priorities for forwardingthe frame based on the different levels of services defined in, e.g.,the Ethernet differentiated service protocol. In this configuration,frames with p-bits mapped to E-EF differentiated service behaviors areplaced in the highest priority queue 102. This queue does not allowframes to be discarded and all frames are of equal importance. In thisexample, queues 104 and 106 are allocated for forwarding frames with theassured service class of the differentiated services and frames areplaced in this queue according to their p-bit assignment. In order toprovide the level of service desired for assured services forwarding,each queue may be assigned a guaranteed minimum link bandwidth andframes are not re-ordered. However, if the network is congested thequeues discard frames based on the assigned drop precedence. Queue 108corresponds to a “best effort” queue. Frames placed in this queue aretypically given a lower priority than frames in queues 102, 104, and106. Queue 108 does not re-order the frames or allow for drop precedencedifferentiation.

While in the example above, an incoming frame was placed in one of fourqueues based on the p-bits 24; any number of queues could be used. Forexample, eight queues could provide placement of frames with eachcombination of p-bits 24 in a different queue.

In addition, the p-bits 24 can include congestion information in theforward and/or backward direction. This congestion information can besimilar to forward explicit congestion notification (FECN) and backwardexplicit congestion notification (BECN) bits of the frame relayprotocol. The congestion information signals a network device, forexample, edge nodes or CEs, to throttle traffic until congestion abates.Out of the eight p-bit combinations, two combinations can be used forFECN (signaling congestion and no congestion), and two for the BECNdirection.

In addition, the canonical format indicator (CFI), a one bit field inthe Ethernet header, can be used for signaling congestion, or other QoSindicators such as frame drop precedence. The use of the CFI field inaddition to (or in combination with) the p-bits 24 allows for support ofadditional PHBs. The p-bits can be used for signaling up to eightemission classes, and the CFI is used for drop precedence (two values),or a more flexible scheme, where the combined (p-bits+CFI) four bits cansupport 16 PHBs (instead of 8).

Referring to FIG. 7, an example of the assignment of p-bits 24 torepresent nodal behaviors by mapping the p-bits 24 to combinations ofthe Ethernet differentiated service PHBs is shown. This assignmentdesignates four groupings of nodal behaviors: E-EF, E-AF2, E-AF1, andE-DF. Each of the E-AF levels includes two drop precedence levels (i.e.,E-AFX2 and E-AFX1) and thus, is assigned to two combinations of p-bits.The E-EF nodal behavior is mapped to the ‘111’ combination 120 ofp-bits, the E-AF2 nodal behaviors are mapped to the ‘110’ and ‘101’combinations 122 and 124, the E-AF1 nodal behaviors are mapped to the‘100’ and ‘011’ combinations 126 and 128, and the E-DF nodal behavior ismapped to the ‘010’ combination 130. In this mapping of p-bits to nodalbehaviors, two p-bits combinations 132 and 134 are reserved forcongestion indication in the forward or backward direction.

For example, if the p-bits are assigned according to the mapping shownin FIG. 7 and the network includes a set of queues as shown in FIG. 6,frames can be routed to the appropriate queue based on the p-bitcombination. Frames with a p-bit combination of ‘111’ are placed inqueue 102 and frames with a p-bit combination of ‘010’ are placed inqueue 108. Frames with either a ‘011’ or ‘100’ p-bit combination areplaced in queue 106 and frames with either a ‘101’ or ‘110’ p-bitcombination are placed in queue 106. If the network is congested (e.g.,the queue is full), frames in queue 104 or 106 are dropped according totheir drop precedence based on the p-bit combination. For example, ahigh drop precedence (e.g. AF22) frame is discarded before a low dropprecedence frame (e.g. AF21) under congestion. In queue 106 frames withthe E-AF12 designation are discarded before frames with the E-AF11designation. Based on the p-bits, dropping frames having an E-AF12designation before dropping frames having an E-AF11 designationcorresponds to frames with a p-bit combination of ‘100’ being droppedbefore frames with a p-bit combination of ‘011’.

The assignment of p-bits shown in FIG. 7 is only one possibleassignment. Other service configurations and p-bit assignments arepossible. For example, the assignment can include three levels ofassured services (E-AF) each having two different assignments to definethe drop precedence of the frames and two remaining combinations ofp-bits for congestion indication. Alternately, four assured serviceswith two drop precedents could be mapped to the eight combinations. Inanother example, four combinations could be dedicated to fully definecongestion in the forward and backward directions. In this example, twop-bit combinations are dedicated to forward congestion (or lack of), twop-bit combinations are dedicated to backward congestion (or lack of),and the remaining four p-bit combinations are used to define the nodalbehaviors. These four p-bit combinations could include one assuredservice with two drop precedence and two CS services, or two assuredservices each having two different assignments to define the dropprecedence of the frames.

The edge node (at either customer or provider side) may perform IPdDifferentiated services to Ethernet differentiated services mapping ifthe application traffic uses IP differentiated services. The mappingcould be straightforward (e.g. IP-EF to E-EF, IP-AF to E-AF) if thenumber of IP PHBs used is limited to 8. Otherwise, some form ofcompression may be required to combine multiple IP PHBs into one E-PHB.Alternatively, multiple Ethernet connections (e.g. VLANS) can be used atthe access and/or core, each supporting a subset of the required PHBs(e.g. VLAN-A supports E-EF/E-AF4/E-AF3, VLAN-B supports E-AF2/E-AF1/DF).

Typically, a class-based Queuing (CBQ) or a weighted fair queuing (WFQ)scheduler is used for forwarding frames on the egress link, at both edgeand core nodes. The scheduling can be based on the PHB (subject to theconstraints that some related PHBs such as an AFx group follow the samequeue). The use of p-bits to indicate per-hop-behaviors allows for up toeight queues, or eight queue/drop precedence combinations.

Additional information may be available/acquired through configuration,signaling, or examining frame headers, and used for performing moreadvanced scheduling/resource management. Additional information caninclude, for example, service type, interface, or VID. For example, a2-level hierarchical scheduler, where the first level allocates the linkbandwidth among the VLANs, and the second level allocates the BW amongthe VLAN Differentiated services classes according to their PHB. Anotherexample includes a 3-level hierarchical scheduler, where the first levelallocates the link bandwidth among the service classes (e.g. businessvs. residential), the second level allocates BW among the service VLANs,and the third level allocates the BW among the VLAN differentiatedservices classes according to their PHB.

The described Ethernet differentiated services architecture allowsincremental deployment for supporting legacy equipment and networkmigration. Non-differentiated services capable nodes may forward alltraffic as one class, which is equivalent to the E-DF class. Other801.1Q nodes that use the p-bits simply to designate priority caninterwork with Ethernet differentiated services nodes supporting theE-CS PHB. Some CoS degradation may occur under congestion in a networkthat uses a combination of E-differentiated services and legacy nodes.

Referring to FIG. 8, an Ethernet differentiated services network 150having multiple domains 160 and 162 is shown. An Ethernet Differentiatedservices domain has a set of common QoS Policies, and may be part of anenterprise or provider network. The set of QoS policies can includeEthernet PHBs support, p-bits interpretation, etc. Edge nodes (e.g.,nodes 152) interconnect sources external to a defined network (e.g.customer equipment). The Ethernet edge node 152 typically performsextensive conditioning functions. Interior Nodes 154 connect trustedsources in the same Differentiated services domain. Interior nodes 154perform simple class-based forwarding. Boundary nodes 156 interconnectDifferentiated services domains and may perform E-Differentiatedservices conditioning functions similar to edge nodes. This may includeperforming p-bit mapping, due to of different domain capabilities orpolicies.

Traffic streams may be classified, marked, and otherwise conditioned oneither end of a boundary node. The service level agreement between thedomains specifies which domain has responsibility for mapping trafficstreams to behavior aggregates and conditioning those aggregates inconformance with the appropriate behavior. When frames are pre-markedand conditioned in the upstream domain, potentially fewer classificationand traffic conditioning rules need to be supported in the downstreamE-DS domain. In this circumstance, the downstream E-DS domain mayre-mark or police the incoming behavior aggregates to enforce theservice level agreements. However, more sophisticated services that arepath-dependent or source-dependent may require MF classification in thedownstream domain's ingress nodes. If an ingress node is connected to anupstream non-Ethernet differentiated services capable domain, theingress node performs all necessary traffic conditioning functions onthe incoming traffic.

Referring to FIG. 9, an example 170 for end-to-end service acrossmultiple provider networks is shown. The example architecture shows theconnection of two enterprise campuses, campus 172 and campus 194 throughprovider networks 178, 184, and 190. A user network interface (UNI) isused between the enterprise and provider edges and a network-networkinterface (NNI) is used between two providers. The end-to-end servicelevel agreements are offered through bilateral agreements between theenterprise 172 and provider 178 and enterprise 194 and provider 190.Provider 178 has a separate SLA agreement with provider 184 and provider190 has a separate SLA agreement with provider 184, to ensure that itcan meet the enterprise end-to-end QoS. Three Ethernet differentiatedservices domains are shown: Enterprise A, Access Provider 1, andBackbone Provider 2. Each domain has its own set of Ethernet PHBs andservice policies.

Although the basic architecture assumes that complex classification andtraffic conditioning functions are located only in a network's ingressand egress boundary nodes, deployment of these functions in the interiorof the network is not precluded. For example, more restrictive accesspolicies may be enforced on a transoceanic link, requiring MFclassification and traffic conditioning functionality in the upstreamnode on the link.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.

1. A network comprising; an edge node configured to define per hopbehaviors using a set of bits in an Ethernet header of a frame; and acore node configured to receive the frame and to forward the frameaccording to the per-hop-behaviors as indicated in the set of bits. 2.The system of claim 1 wherein the set of edge nodes is configured toprovide conditioning of the frame.
 3. The system of claim 1 wherein theset of bits is a set of priority bits (p-bits).
 4. The system of claim 1wherein the set of edge nodes includes an ingress device and an egressdevice.
 5. The system of claim 1 wherein the edge node includes aclassifier device; and a marker device configured to mark the frame witha particular per-hop-behavior indicated in the p-bits.
 6. The system ofclaim 5 wherein the edge node includes a shaper.
 7. The system of claim5 further comprising a meter.
 8. The system of claim 5 wherein the edgenode includes a dropper.
 9. The system of claim 1 wherein the set ofedge nodes is configured to add a tunnel header to the frame, the tunnelheader indicating the per hop behavior associated with the frame. 10.The system of claim 9 further configured to preserve the information inthe original frame.
 11. The system of claim 1 further comprisingmultiple Ethernet domains.
 12. The system of claim 11 further comprisingboundary nodes between the multiple Ethernet domains.
 13. The system ofclaim 12 wherein the boundary nodes are configured to map the per hopbehavior of the frame between the multiple domains.
 14. The system ofclaim 12 wherein the boundary nodes are configured to provide trafficconditioning for the frame.
 15. A network comprising; a first Ethernetnetwork, comprising an edge node configured to define per hop behaviorsusing a set of bits in an Ethernet header of a frame; a core nodeconfigured to receive the frame and to forward the frame according tothe per-hop-behaviors as indicated in the set of bits and the a secondnetwork comprising; a second edge device in the second networkconfigured to determine the Ethernet per-hop behavior for the frame. 16.The system of claim 15 including determining the frame PHB based onprotocol information.
 17. The system of claim 16 wherein the protocolinformation includes Ethernet port, VLAN-ID, IP DSCP or other L1-L7protocol information.
 18. The system of claim 16 further comprising acustomer edge device configured to set the p-bits for the frame based onthe frame PHB.
 19. The system of claim 16 wherein the core nodes use adifferent network technology than the edge nodes.
 20. The system ofclaim 19 wherein the different network technology includes at least oneof asynchronous transfer mode, a multi-protocol label switching, a framerelay, or an Internet protocol.
 21. The system of claim 19 wherein theset of edge nodes is further configured to map the Ethernet per hopbehaviors to a set of bits in a frame according to the different networktechnology.
 22. The system of claim 19 wherein the set of edge nodes isfurther configured to map the Ethernet per hop behaviors to a set ofconnections in the core nodes.
 23. The system of claim 19 furtherconfigured to preserve information in the frame.
 24. The system of claim19 wherein the set of edge nodes are further configured to encapsulatethe frame for delivery on the core nodes.
 25. The system of claim 24further configured to tunnel the frame.
 26. A networking devicecomprising: a behavior aggregate classifier device configured to receivean Ethernet frame and classify the frame based on at least one of a setof priority bits and information in an L1-L7 Ethernet header, theclassification including defining a per hop behavior.
 27. The device ofclaim 26 further configured to determine a bandwidth profile based onthe classification.
 28. The networking device of claim 26 furthercomprising a marker device configured to mark the frame header with aparticular per-hop-behavior indication.
 29. The networking device ofclaim 26 further comprising a shaper device configured to receive aframe from the marker and determine a behavior based on the per hopbehavior.
 30. The networking device of claim 26 wherein the marker setsthe priority bits in the frame to a particular combination.
 31. Thenetworking device of claim 30 further comprising a frame meter.
 32. Thenetworking device of claim 31 wherein the frame meter device isconfigured to determine temporal properties of a set of frames.
 33. Amethod comprising: configuring an edge node in an Ethernet network todefine per hop behaviors using a set of bits in an Ethernet header of anEthernet frame; and configuring a core node in the network to receivethe frame and to forward the frame according to the per-hop-behaviors asindicated in the set of bits.
 34. The method of claim 33 wherein the setof edge nodes is configured to condition the Ethernet frame.
 35. Themethod of claim 33 wherein the set of bits is a set of priority bits(p-bits).
 36. The method of claim 33 wherein the set of edge nodesincludes an ingress device and an egress device.
 37. The method of claim33 further comprising: configuring the set of edge nodes to add a tunnelheader to the frame, the tunnel header indicating the per hop behaviorassociated with the frame.
 38. The method of claim 33 further comprisingconfiguring boundary nodes between multiple Ethernet domains to map theper hop behavior of the Ethernet frame between the multiple domains. 39.The method of claim 33 wherein the Ethernet network is a first networkthe method further comprising: configuring a second edge device in asecond network to determine the Ethernet per-hop behavior for the frame.40. The method of claim 39 further comprising: determining the frame PHBbased on protocol information.
 41. The method of claim 40 wherein theprotocol information includes Ethernet port, VLAN-ID, IP DSCP or otherL1-L7 protocol information.